Yes, same issue here in Finland with my Sub 37 (serial number mid 1500). I was surprised about the gap and those clearly visible square holes. And then I found this thread. Can I now calm down and expect some help from Moog with this?
Moog have sourced some black felt lining material for use with piano keyboards… if you are interested in having this material installed on your own keyboard, contact the Moog service department directly.
cheers,
Amos
dang, i had been hoping for red felt.
but black felt is ok, too. anything is better than those ugly gaps. 
i hope this is a field upgrade?
hi, can anyone confirm, is this a matter of “do-it-yourself” install? or does the keyboard need to go back to Moog? or to a local distributor ? or service centre?
the square holes are really unsightly. especially when the Sub37 sits on a keyboard stand and the angle pushes them right in your face.
this problem is even is quite obvious on the front cover of the current SOS!!
Cheers,
Blackout
i just contacted tech support about this: at first, they suggested that i send in my s37 and have them install it for me. but after i told them that i have built and modded my share of diy and vintage synths before, they agreed to send it to me as a ‘field’ upgrade instead. i’ll report back when it arrives and let you know how hard it is to install. but how hard can it be to take apart your s37, glue in a strip of felt, and put it back together?
Thanks,
i have the same Problem with my keys.
Same thing here.
Me too but I think I can source my own length of felt (or similar) and fix it rather than let the Sub37 out of my sight 
R.
Please, tell in this forum how you did with your various kinds of felt adventures (with Moog tech support or without it).
I am going to cut a strip from this …
http://www.amazon.co.uk/gp/product/B00DSO3T8A?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00
.. and stick it to the vertical part of the panel just behind the keys. the 2mm thick felt should be enough to conceal the key ‘holes’
I have chosen black but there are plenty of other colours
R.
The expression “to make a mountain out of a molehill” comes to mind here..
Well at least that one killed the discussion here once and for all. And yet this molehill still annoys at least myself a bit.
my first post was around 5 months ago about this problem i must say i would have thought that Moog would have come up with a solution to this by now especially as they said they would be addressing the issue…
they have. amos posted about it about a month ago:
as i mentioned earlier, i did contact them and they said they would send the kit over to me. still hasn’t arrived, though. : (
thanks bartleby. you are right.
however has anyone recieved the upgrade or kit?
Yeah, i was told i would be sent one a few weeks ago but nothing yet…
still nothing even 1.5 months after support told me they’d send me this kit. 
Yeah, still no felt strip although Moog promised to send me a fix kit 1,5 months ago
I never even noticed it. I love the feel of the keys on this keyboard, it blows my DSI Prophet 12 away!
i finally received my ‘felt strip kit’ two weeks ago - almost 3 months after they said they’d send it to me. i installed it yesterday.
it consists of a strip of foamed rubber with some adhesive on one side and a wider strip of some kind of black textile glued to other side. they call it a ‘felt strip kit’, but the textile doesn’t actually seem to be felt, but rather some kind of velvet-like material.
installation is easy: you remove the four side panel screws that hold the control panel in place, lift up the panel and stick the adhesive side of the ‘felt strip kit’ underneath the front lip of the control panel. the textile strip then covers the upper part of the keyboard - including those ugly gaps.
i think you could easily build something like this yourself, if you prefer a different material or color (red or yellow might look nice), or aren’t patient enough to wait for months for it to arrive from moog music.
here is a few pics:
