No, there's more than headspace to worry about.
1. Sticky or tight or rough chamber.
2. Failure to feed.
3. Failure to smoothly and crisply eject.
4. Sometimes, failure of the magazine to take more than 3 shells, though it should take 5 and store 4.
These are all very common problems that arise whenever anyone builds a sporterized mauser. Sometimes, the problems are worked through and fixed by a competent gunsmith, . . . sometimes NOT.
I would never buy this rifle until you have (i) checked the headspace with the proper gauges, (ii) loaded it up with 5 dummy rounds, and (iii) made sure that at least the dummies cycle well.
Regards,
Mannyrock