Iran has always adopted foreign weapons and uniforms.
During the time of Napoleon the iranian army switched from blue to red uniforms and otherwise from year to year - as an effect of succesful french and british diplomats.
Between 1900 and 1918 the regular imperial iranian army had british-style uniform, the police had swedish (yes - swedish
) uniforms and the cavalry was equipped with uniforms of the russian cossacks.
And before Iran was invaded by the allies and forced to declare war against the German Reich its army had german Wehrmacht uniform style - including the german officer caps and german steel-helmets.
After WW2 the german uniforms were replaced by US uniform.
Even after the Shah has been deposed decades ago its not surprising that Iran still have its exotic mix of uniforms and weapons.
US-Uniforms of the style of the 80ties, russian, british and US-tanks, US-and russian planes and german and russian stormrifles.
At least we never had the german pickle-helmet or italian helmets with these feather-ornament