I've never seen "cartridge guide spring" listed on any schematic. There is a tiny slot above the chamber and a tiny metal protrustion that could be a guide of some sort.
Messed with the feed ramp/feed throat for an hour and a half last night and its feeding worse than before. Not feeding the shorts anymore, had some failures to extract, double-feeds, etc. I'm going to keep messing with it, but it's been disappointing so far. Looks like this might not end up as a reliable old .22 for me!