Nice job, it may not be 100% accurate, but anyone who has seen the movie would recognize it.
For the original poster, the problem you will have using the Texaco trailer is it is round, not an eliptical trailer like in the movie. If that doesn't bother you then it is a good choice being much easier to find and about half the price of the Beale tanker. Lindberg has reissued a tanker trailer too, it isn't right either but it is eliptical at least, also pretty cheap, you can find it in a set with a Dodge L-700 tractor for $30-40.
I've also used Sourkrout's several times and never had a bad experience, but I haven't bought from him in about a year. With a small one man company like that, service can change very quickly if the get overwhelmed with outside issues.