sure
The 180's I mentioned in my post were all HP's. A JSP slug should be a bit "harder", and may perform a bit better than the XTP hollow points, I used. I'm betting your Marlin is twisted 1-38" and should really like the short, stubby 180's.
I've seen factory 180 JSP's on a few occassions, but the prices were too high for me to buy. Sounds like you got a deal. They will be grim death on 'dillo's and any small to medium pig in the 125-150 class I feel certain.
They certainly will be "safe", you just will not get the penetration on larger, bigger animals that the heavy slugs will produce.