Cute machines! I have no help on the cams but love the color (and price!). A 99 and 221 aren't really the same except that they're both lightweight little straight stitchers. The 99 is a 3/4 machine with a horizontal (drop in) class 66 bobbin. The 221 is considered a 1/2 size machine with a vertical bobbin that is unique to itself, 222 and 301 machines. Both sew very nice stitches and both are fun machines to use made my singer, use standard needles and do the same thing so they're close cousins, I'd say. It looks like your 99 is missing the bobbin plate, which is common from the one's I've seen. Your LSMG/LSMS may have a graveyard of parts machines to grab one from. Have fun with them, you got some great deals and good little machines!