No authority on T/C's, but have had a few. The frames with the engravings should be the prepresent G2's, which look like a smaller encore? The earlier contenders should have one screw for a trigger stop, and one like a sear adjustment? I got mine tweaked so it just breaks with a little movement of the trigger, and with the trigger stop, there is hardly any play after the sear breaks. I prefer the older trigger, because of this, and I can get a real nice trigger without having to get an expensive custom trigger job. With the encore/G2, they usually have to get a trigger job. I've heard you could do your own trigger jobs, but I'm not one to want to mess with it. Had one experience trying to do a kitchen table trigger job on a 1911 I once had, and the sucker went full auto!!!! I tried the Encore, and even though it can handle higher pressure rounds, it is I think a pound heavier, which makes a big difference to me. Plus, it doesn't have the same feel as the original contender, and the encore also has a farther trigger reach, and reason I sold the encores I had. Just hard to beat the old contender design. And from what I was told, the G2(replacement for the contender), isn't that much stronger than the old original. There are several different safeties on the different contenders? Some had the old screw like switch from centerfire to rimfire, one you push from side to side, and I think the most recent was you just switch a lever about 45 degrees or so, from centerfire to rimfire. One advantage of the G2 was that if you decided not to shoot the loaded round, you could bring the hammer down, and if you wanted to shoot again, you just pull the hammer. With the original contender, you had to open the action then pull the hammer. Personally, never had a problem doing it, and don't really see the advantage on the newer style? As far as scope bases, I use standard Weaver bases(around $8). It has multiple slots. so you can adjust eye relief to your liking. It utilizes the four holes under the factory sights. There are 6 hole custom bases out there, made by various folks, but you have to drill 2 more holes, which will add to the cost, along with the bases running as much as $88 with rings! These are preferable with the big chamberings, but I've used the standard 4 hole weavers with a couple 45-70's I had in the past, with no problems whatsoever. And since your talking 300 Whisper and .223, you don't have that much recoil to need that much base and rings. But if you really wanted more, you could add up to 4 rings on this base. With these 2 cartridges, you can run pressures up to rifle pressures, because of the smaller head diameter of the case. When you start going cartridges bigger than these or .357 mag size cartridges, then you have to watch your pressures. I have a 14" .223 I'm parting with, a 10" 7x30 Waters
http://www.reloadingroom.com/page43.html
with dies, brass and stuff, and might have a scope base too? Might have a scope or 2 also????? Sorry for the long post. I guess it shows that I like the contenders??