Mystery Parade

I recently stumbled across some photos of what appear to me to be the Seattle Cossacks in a Memorial Day Parade. In the one photo of the PD bikes (last photo) it appears they are riding Panheads so it must be 50's. A sign in one of the store windows says "“Memorial Day May 30th.” I think the only year in that decade for which Memorial Day fell on the 30th was 1955 so that's my best guess. Any other theories?

Jimmy in Frosty Young's VFW Uniform

I got a little help from Hurry-Up Nate. He confirmed the police bikes are probably pre-58 Panheads as they have rigid style crash bars. Both the Cossacks bikes and the uniforms appear to come from the period in which the team was sponsored by the Veterans of Foreign Wars (VFW). I don't know the exact dates of the VFW Cossack years (a little help, anyone?) but Frosty Young was member #49 which I think may have made him a member active in the mid-fifties.