Im gonna buy new graphics card, need help with PSU opinions.

Disclaimer: Not an expert; I encourage you to get a second opinion if possible (especially since I can't answer your question about the 12v rail.)

Having said that: I wasn't able to turn up anything at all about the specifications of the motherboard in the Thinkcentre M72e--I'm assuming you have the tower version of that model and not the small form factor version? You also didn't say what kind of case your friend is offering. So if you haven't already done so, the first thing I'd do is double-check that the MB's mounting points are in the right places to match the standoffs in your friend's case (or that the standoffs can be moved to match them,) that the MB will accept the connectors supplied with the Seasonic, and that the power supply itself isn't too large to fit into that case.

If that all looks good, and if the free/cheap case is one you like and is in acceptable condition: in your shoes, I'd go with that and the S12-II. Seasonic comes highly recommended, and the S12-IIs are Tier Two units, which means they're quality PSUs with a decent track record for stable and reliable service. 430 watts should be adequate for those system specs, and the unit should be compatible with your new video card.

On the other hand, I can't find a single person here or elsewhere who's got anything good to say about Thermal Master PSUs. They're apparently a cheap line that Cooler Master only sells bundled with some of its lower-priced cases. None of them are even mentioned on the tiered power supply list, and I found reports that they've been known to die within hours of purchase or actually explode under load. So yeah, for the safety and longevity of the system, I'd choose Option 1.

In the event you do go with one of the Cooler Master cases for whatever reason, I'd really recommend replacing the PSU with a better one as soon as you can manage it. You might get lucky and have no problems with the included Thermal Master units, but a bad one could kill all your other components. (Further disclaimer: Any PSU could turn out to be a lemon, including the Seasonic, but your odds seem much better with that one.)