Oleg Mitiukhin
No, only a zip with one .obj and optional .mtl and .jpg files.
I must say I also don't see that changing anytime soon. For all types of media files, we have thus far only allowed one format (converting to that if necessary, but on md the primary image format is jpg, pdfs are pdf, videos are mp4, etc.). That makes handling the files a lot easier. If we were to introduce .glb at some point, we'd have to do away with the existing solution. In effect that would mean to convert everything that has been uploaded thus far.
.glb looks promising and I can see that happening at some point in the future. But certainly not anytime soon (unless somebody volunteers to implement it all the way, including the conversions).