Your rear backlite is urethaned in. You don't NEED a new moulding, it'll just look like shit. I don't know what glass co. told you $250, but a labor cost for this job at my glass shop would be $50. $250 was probably for glass, moulding,labor, and glue. Once you have the glass out, trim down the old urethane as close as you can with a long knife (or utility knife) DON'T scrape every little bit of it off because urethane sticks best to urethane, and the main reason for trimming is because of the height when you set in the new glass. It is very important that every little scratch from the utility blade gets covered with pinchweld primer, or else you'll have a rust bucket within a few years time. Clean and glass prime the new glass. I would strongly suggest a new moulding. Shoot your bead of urethane, plop the glass in, and push down around the black band on the glass with the palms of your hands. Done! With that said, I would leave this to glass professionals. There are specific adhesives and primers that need to be used, and if your urethane bead isn't straight, it can get quite messy. I would abseloutely not use anything other than urethane, unless you wanna be picking up thousands of glass bits off the road your first time down the highway. In my 12 years of autoglass, I have seen some nightmare installations of DIYers. Any other questions, give me a shout. Jer