Authetication help? 1601

[SiSiSenor]

I bought my very first Rolex recently from an online seller over eBay. Fully aware of the risks, but thoroughly doing my homework on the watch as well as the seller, I went ahead and purchased it after winning the auction. I paid ~$1750 CA. for it, and it seemed fair compared to the going prices of similar watches. The serial number fits with the advertised production date of 1977, and the movement seems to match as well, but I have yet to have it professionally authenticated. The seller has a return policy, but I was wondering if I could get a quick opinion on here before taking it somewhere to have it looked at. The watch itself is in beautiful condition, and runs very well.

I did post a similar thread in another part of the forum in few weeks ago, but only became aware of the WatchOut! part recently. If anyone else here could have a look, it would be great.