Note here:
early built Classic I CRTs are plug-and-play with the SE & SE/30. At some point during their run, they converted the yoke wiring over to what was seen on the Classic II
To the moderators: Please consider making this a sticky as these questions get asked quite frequently on here. There have been some recent discussions about the CRTs used in compact Macs, specificallly in reguards to compatibility between machines. Having worked inside of dozens of compacts, I...
68kmla.org
All the same, I took a similar gamble on a Classic that showed up on the local classifieds.
If the wiring doesn't match up, then its up to you to decide whether or not swapping the yokes is worth it. It takes some adjustment which can be tedious, but it's not impossible. ALSO be aware that you're dealing with lethal voltage. On the assembly line, this adjustment was done while the Macs were powered on (at least with the original Macintosh per historical photos).
FDDs should be compatible. Here's a nice reference for the types of FDDs to check just in case
https://siber-sonic.com/mac/superfloppy.html
Sadly analogue boards themselves won't be compatible, but I believe the flyback transformer is, but I can't say 100% off the top of my head. Still worth salvaging.
That's really all I got out of my parts Classic, to be honest.