I believe all single plane M1 intakes for standard heads non W series heads are spread bore and I've never seen an M1 specific to the W series heads. I'm sure they are out there but I haven't seen them. Every M1 I've seen since looking for info on the M1 leads me to spread bore intakes.
I have never seen or remembered a spreadbore intake for the W2. The W5 is the only W head to have a spreadbore intake and it is almost exactly the same as the LA intake save the relocated bolt holes that are of course, moved out.
