Myself, I perfer the ability to look/see/touch as compared to buying something on line.
Might pay a lil bit more at a gun show, maybe not and you dont have to deal with an FFL to pick it up. Its Yours, right now.
If you can't find the caliber you want? The receiver appears to be a good deal,buy it. No biggie, Look in the "For sale" part of this forum,you can always sell the barrel you have and buy or trade for something you want.
Personally, I would be exploring any local sort of forums with many "looking to buy" posts before I would venture into either a gun show or a web based seller.
Here is a good example, I know of a real nice Contender outfitted with a 45-410 barrel , hes a local guy and cant find anyone interested in buying it. Hes asking $275, now I dont want the barrel, but I figure I can sell it here for round $150. This means Im into the reciever, which is 'like new, for $125.
Look before you leap.