www.beartoothproducts.com/ they have 3-piece neoprene kits in snow camo, regular camo etc. for rifles shotguns etc. you can also just buy the barrel sleeve, have bought them from Russels forsure, can't remember if i've seen them at wholesales or not?
If you call the open stuff then i would say at minimum get that barrel covered up. I try to buy guns with dull matte finishes for calling whenever possible too.
However i've shot lots with shiny guns too but i try to get my butt in the shade or in some good cover...if in the wide open then keep the gun low and only pick it when your ready to shoot.
A fellow on predator masters website doesn't follow the camo game at all and kills between 100-200 a year for the fur business, he wears carthartt jacket, cowbow hat, shoots a .220 swift and is good with it to long ranges and calls strictly with a crit'r'call peewee....so its not like its necessary but it helps. So he obviously knows how to set up properly and keep movement to a minimum. Just using as an example...
I specifically remember one coyote called in to about 200 yrds with the usual rabbit blues, i lip squeaked it the rest of the way and every time i even wiggled my tikka t3 lite (black matte) the coyote stopped and looked...i held still and kept giving the odd lip squeak...but i had to wait until the coyote went out of sight before i could get the gun to shoulder. It was resting on shooting sticks with barrel in the air, i was on side hill mostly in shade up against bush, the gun barrel was in the sun and if it moved even an inch that coyote would stop and stare...so wasn't getting away with anything until it went out of sight...when it came back into view it was 120 yrds so i took her then.
I usually wear camo and feel headnet/gloves are musts and also the barrel too. I've shot lots wearing jeans with only camo up top but you have to be smart about your set up, understand how good your camo is for the spot...the weaker it is the less movement your going to get away with.
Hope that helps. Oh, and being from the Calgary area i wouldn't white camo my gun at all. I believe in lighter camo's altogether for all conditions around here...and do have some winter camo for when it is cold and snowy around here but we have lots of chinooks and no-snow periods so most of the time i'm in high plains type camo's....the gun is small enough that if you can just keep the glare off it you should be alright. If all you ever do is call in the snow then white would be great.
B