EDIT: Better photos down the thread
These shifters were part of a trade that I did for a Simplex SX-610 RD and sans-logo SJA 102 FD - I assume they were originally part of the set. Outer plates bear the Simplex name.
I came up empty on Velobase - thought I'd ask here. If nothing else, I can add them to the Velobase archives once they've been identified.