Don't need to look at the serial number... the barrel stamp will tell. Bought in 2018/2019, it's most likely a Remlin. unless it was on the shelf for quite some time.
Based on your description, I would estimate value in the $500 - $700 range.
Doesn't matter what you paid for yours "back when Walmart put them on sale". What matters is what they are going for right now. The Ruger 1895's are not priced anywhere near that low either.
Mitchell Mountain, go to gunbroker and look at what the bids are on the non JM Marlin 1895's, or better yet, look at the completed auctions. You'll find them going way north of $500 to $ 700.
If you sell here, most likely being a Remlin, disclose if it has any function issues.
Jerry