TA outer ring is 50.4 bcd but it made different inners. The cylotourist inners are 80 bcd. I thought that the smallest inner was a 26. In any case if the bolt hole diameters all line up with your small chainring, then they are all 80 bcd chainrings. The other sizes of TA rings were 152 and 116 bcd.

I wish I had known this earlier - TA Cyclotouriste

Sutherlands 6th has the smallest chainring at 26 teeth. It's a 6 bolt pattern. The BCD is 80; from hole center to hole center, the measurement is 40.