Well, I'll be! We were just talking about R & E Mfg. Co. gem pans (and Waterman gem pans) as always being side gated and, yet, yours does look to be bottom gated. These are fairly common, nice pans made in 11 styles or shapes of cups. 1-8 are all shallow cups; 9 is a golfball pan, 10 a popover pans and 11 a french roll pan. Not too much value for these pans but it's fun trying to put a full set together. They sell in the $15 to 50 range usually.
Steve