FYI that gun is one of the early or first RSM models. Ruger does not have a clear path on serial numbers i.e. this 780 serial number prefix is older than the 750 ones. This older model has a stock a couple inches longer (maybe only 1.5, I've not actually measured) with the barrel band sling swivel going through the stock. Most definitely CRF. These older models are a bit heavier. There was a post on here a while back talking about there actually being 3 iterations, with the third being the lightest weight. I don't have any personal experience with that but hope to learn more.
All the RSM's I've shot are good accurate shooters. I have one of these 780 models in 416 Rigby. Several of the 750 models plus several of the smaller caliber 760 Express models. They are all good shooters and top quality guns that seem undervalued for the quality.