Westernfield was used my Montgomery Ward. Looks like yours was manufactured by Mossberg. I would say the value would range from $100-$350
Richlands were imported from Spain and Italy. Price would run from $150-$400
The Ithica looks like a field grade model, some of the barrels were reported to be weak, low pressure shells should be used. Prices on the low end would be $150-$700
Winchester manufactured close to 250,000 model 50s between 1954 and 1961. By the looks of your serial # yours was made in the ealier years. $150-$500 would be close to auction price.
Winchester model 61 were built prior to WW2 Both round and octagon barrels were made. Prices on this gun range from $300-$800. Perfect near new condition would get you maybe close to the $900 range. I hope this helps. A gun dealer could get you a more accurate price due to the auctions that most of them attend. QD