I agree w/Bish,a soak in hot water and a gentle bending should fix it.
Unfortunately, Revell got it wrong. The OH-13H was not used as an air ambululance for MASH units in Vietnam. The OH-13H was used early in the war as an early gunship prototype, as depicted in your kit, and later as an unarmed scout / observation helicopter (OH). The earlier H-13D as kitted by MRC/Academy was used as a MASH air ambulace in the Korean war. By Vietnam, Hueys were used as DUSTOFF aircraft (air ambulances).
I would build it as the armed gunship.
What was used as a mash helo ? Huey