The seller did not disclose it's missing?
The proper factory recoil lugs are available from Western Gun Parts and Numrich, as well as a few others, online.
I personally wouldn't be putting any more cash into that rifle, if its been put into a different stock from its original.
I have a very similar rifle, with the same rear sight and tapered, non stepped barrel. It was rebuilt between WWI and WWII by European companies for offshore sales.
Some of them have dual set triggers and are actually very good shooters.
The stocks, usually aren't cut down military types and often have Schnabel fore end tips.
Your stock appears to be a military stock that was cut down for sporting purposes. I can see it happening. The commercial stocks had very thin wrists and the inletting was often sloppy as well, without the cross bolt. This lead to the wrists cracking and breaking.
BSA, Mauser variants often had similar issues, if they weren't glass bedded. They tried to get away cheap, by leaving out the cross bolt and installing a tapered wood dowel through the stock, right in front of the mag well. When the glue dries out, the dowel loses its grip and might even fall out.
This doesn't mean your stock isn't useable for your purposes. All you need to do is a bedding job. Lots of different but appropriate materials available to do the job for under $20.
That little rifle in your pics is old school, before scopes were cheap and readily available. Sort of the Rem 783 or low end Savage/Mossberg of its period. Just like the other rifles I mentioned, that rifle is very serviceable and will do everything you need it to do, within your shooting limitations, with open sights. It's hardly mentioned anymore but back in the sixties, when scopes started appearing on more hunting rifles, comparisons were made, utilizing proven skilled shooters on rifles with both types of sights.
It was established that the naked eye, looking over iron sights was just as accurate, out to appx 150 yards as a scoped rifle. Diopter type sights were equal out to and past 200 yards.
Here's the conundrum. Can you afford to get the rifle's receiver properly drilled and tapped, purchase and mount bases, rings and a scope that will stand up to the generated recoil? Is it worth the extra expense to you?
Commercial sporter stocks for 98 type receivers, often show up at gun shows and on EE exchanges on this site and others. There are all sorts of polymer stocks available for them as well as laminated. Depending on your budget again.
Your rifle could quite easily become a very decent sporting rifle.