Unless you want something way out of the ordinary, just go to the website. I don't know that I've ever had reason to call, but everything I've ordered from them has been run of the mill stuff.
Prefit Barrels with Osprey blanks
patriotvalleyarms.com
I called in about wanting a prefit for my CDG in something they didn't carry on their site.
Talked to them on the phone, got all the details and answers sorted out and got it ordered.
There is no harm in calling during phone call hours if you have questions about exactly what you want to order or want something a bit different.