How long an order takes depends on whether or not the shop's supplier has one or not. Some times it can be about the shop's credit rating, but not often with a shop that's been around a while.
Mind you, if you go to Ruger's site and click 'Buy now.', it shows that not even those 2 retailers have any Mk IV's at all. So it's highly unlikely your local shop can or will get one faster than 4 months. If a retailer can't pick up the phone and call his supplier and tell you if they can get one, don't sign anything that lends 'em your money interest free.
Cabela's shows Hunter Target as Back orderable, and plain SS Hunters as 'Limited stock' but ships to your local store in 5-8 days.
"...availability of internet sales..." Won't matter in this case.