If it's just the board, you'll probably get away with it. There's a threshold for a certain number of items changing. 5 from 10 IIRC.
New board will usually trip the MAC address and disk controllers check. Keep the same GPU,CPU, RAM and drives and it should be fine.
Last time I checked, 7 would still activate. A fresh installation requires patching up before it'll activate as the root certificates to connect to the servers were updated at some point.
Motherboard and CPU will likely trip it.
Windows 7 can still be installed and activated after end of support
Which is fine, but is it even possible to reactivate W7 these days since it's out of support?