Are they both bias ply construction? Should not make a difference if they are. I recall a Michelin caution for steel belt radial on cars that the bias ply go in front if a driver were going to mix bias and radial. That was supposed to promote understeer which, for some reason, they considered safer. This was early before any other tire maker was into radials except maybe Pirelli.
I have a Michelin PP SC on my front and an Achilles steel belt car tire on the rear and have yet to catch on fire or crash and burn....