The Marine Corps used both UH-1Es and HH-1K for station SAR duty and I've seen them painted both all red/orange and red/orange and white.
For the UH-1E in Vietnam you have a lot of different options. Best bet is to go to a place like popasmake.com or scarface-usmc.org and pick a picture you like and match that aircraft. The UH-1E squadrons in Vietnam were VMO-2, 3, and 6 and HML-167 and 367. You can google those too to get more choices.
Basically in general the gunships had the doors and hoist removed and the slicks didn't but you will find almost every conceivable combination - gunslicks with hoists and doors but no door guns, slicks with door guns and no hoist, particle seperators, no particle seperators, etc.
Markings also varied between tactical and hi-vis. Some squadrons had their own specfics marking (for example VMO-2 and 6 had two white bands painted on top of their blades, VMO-3 had one band) but even that is hard to keep track of as aircraft moved from squadron to squadron. For example, VMO-3 became HML-367, and then later HML-367 gave up its Hueys to other squadrons and became all Cobra (which they got from VMO-2).
The Strella picture posted looks like it came from HML-367 in Okinawa around 1975 so it is post Vietnam (unless they had them when they participated in Frequent Wind). The photographer used to hang out either here or at HKN perhaps he can shed some light on how widespread their use was.