All the 5 inch guns... 645, 745, 845, 4506, 1006 use the same standard weight spring being the 210610000 unless your using reduced power loads ie. wadcutters then the wadcutter spring 200710000 applies.
All the compact 9mm guns use the same recoil spring too, that being the 100950000 which is painted a sorta icky green color. Brownells has them.
CS45 flatwire spring... Same spring for all variants. Don't fret about the at rest or free length on the bench. What's important is the wire thickness x coil count. Of course I can't measure those springs from here but they both appear to be the same spring. Know that those flatwire springs will take a set once installed and broken in at the range losing about a half inch of free length. They do tend to be a bit disagreeable to install & cycle by hand when new but nothing to be concerned over. Jam the new spring in there, head to the range and treat it like a rental car
. You don't have one of those shockbuff thingies in there do you?
Cheers
Bill