If that's an IBM, it must be rebranded - the L-shaped Enter and short Backspace point more towards East Asian origins.
'connie-sewer' for 'connoisseur', that took me a second...
I thought the 'dropped' cursor T was interesting; I don't remember seeing that before. Is it a PS/2 connection and buckling spring, or something else?
Show Image(http://i.ebayimg.com/10/!BReu!Tg!mk~$(KGrHgoH-CQEjlLl1C88BJ-MQ4U3lw~~_1.JPG)
I'd be almost 100% certain that that is not an IBM board, although I remember seeing it while searching for a Model F on ebay, so maybe that's where you found it?
Wrong, its just the larger ANSI Enter.
Probably it's a KB6551 made by NanTan sold as Chicony, Nantan, Zeos and more ( FCC ID FMAKB6551).
check Scarry's listing. he often lists this one on eBay.
Mostly simplified alps white on a plastic face plate. not sure if real complicate alps/metal face plate version exist or not.