I'm pretty sure the 1200LC stuff fits directly onto the 1250. Engine related stuff like head protectors, headers and crash bars don't, but everything else has remained unchanged.
I bought the Puig support brackets to replace the single sided Wunderlich one that was fitted to my GSA LC 1200 and they did not fit. The mounting holes were incorrectly aligned. Sent them back to supplier and bought a pair off eBay from Lithuania. Well made and finished but did take a couple of weeks to arrive. Were £30 +£5 postage...