FWIW, I have never seen an Israeli Mauser chambered in 7.62x51 with a poor bore. The conversions were done long after Israel was declared an independent state. Lots of reasons for the conversions but mostly their Mausers chambered in 8mm were well used and in definite need of an FTR. Israel decided to go with the new NATO chambering for ease of procuring parts and ammunition as well as standardizing their front line ammo requirements. During their previous wars they had a huge problem with firearms chambered in various cartridges and many immigrants that could only speak their mother tongue but no Hebrew etc.
Luckily many were familiar with the Mauser system so retaining the K98 was a good idea, especially as reserve war stocks which many were relegated to.
Very quickly after they became a state Israel moved away from Mausers and Lee Enfields onto FNs and many other systems. Eventually they made their own and produced the excellent GALIL chambered in 7.62x39 and the UZI in 9mm to name a few.
There are some Israeli Mausers chambered in both 8mm and 7.62 that bear very rare makers marks and dates. I have seen more than one being used as representative pieces in collections where the only thing about them that is incorrect are the Star of David stamps on the receiver rings. They bought those rifles from whomever would sell or give them to Israel. They also captured thousands of Mausers and Lee Enfields from the Arab States and later Soviet made firearms/ammunition/tanks/aircraft/vehicles and supposedly thousands of pairs of discarded boots left on the battlefields.
All of this needs to be taken into consideration. I have a Czech Rampant Lion crested model in 8mm with all matching numbers with a small Star of David stamp on the left side, beside the serial number. Everything else is original. It is still full of what may or may not be the original Czech grease. The other is a very well worn SWP45 conversion in 7.62x51. Not one number on this rifle matches another but it does have the SoD stamp. The stock is very dark and bears lots of dings and scrapes. For some reason, it has an excellent bore and shoots better than I can hold it. I love shooting this rifle. Recently I sold a Belgian made post war 98 made for Israel in 7.62x51. I have no idea if it had been issued. It looked perfect, was full of grease and had the Israeli Shield with sword on the receiver. I couldn't bring myself to shoot it.
Israeli Mausers, like Carcanos and South American Mausers are the Rodney Dangerfields of the milsurp collectors field. They are steeped in all sorts of violent history, including blockades, insurrections, political agends, racism and religious affiliations not to mention many hard and bloody battles. About the only Mausers less sought after are the Chinese versions which saw just as much use.
Anywhere from $250-$600 depending on condition and maybe desirability of certain manufacturers and dates.