5 quick operation and Maintenance Qs

Pulled the jet out. On the side it says "552"

I'm assuming this means .0552? Thousandths? Every jet I see in the comparable range says the measurement in 2 digits. I'm assuming this is slightly larger than a #55? Is that right? Everything i see online says to use a 56,57,58 etc... Plugs aren't saying it's running rich, and it seems lean, so what would the best option be? Also mine did not look clean like the one above. Mine is greenish and likely does not have the polished surface inside. I blew the jet out with carb cleaner, and put it back in till I know what I need. I also noted the spring on the float had moved off the float when I took it apart, not sure if that matters or if it's just to help reassemble the carb. The float level also was a bit higher than what I adjusted it to a few months ago.