The Syracuse and early Fulton Hunter Arms guns had a straight angle.
Mid-1890s to the 1913 "New Design" guns, both Reg and FW frames, had either, but in my experience mostly the angled wood/frame juncture
Post-1913 were straight but I've seen as late as 1916 with an angled juncture
FW frame with straight juncture
FW frame with angled juncture
Please post if you have an earlier than 1895 or a later than 1916 gun with the angled juncture.