Normally the RSMF3 is taped at a class 2 (63.5mm) taping width (as the dimension “D” in the image below). The -C1 denotes class 1 (narrower) taping. It’s just packaged at an inside tape to inside tape spacing of 52.4mm instead of 63.5mm.
There is no functional implication for this suffix code.
Applicable Part Numbers