I have a .50 Ithaca Hawken that I shoot a lot, and I love it. It was made from a kit, marked with a K on the bottom of the barrel (factory guns are marked with a serial number), and I know three other guys who have them in this area (Ithaca NY). None of us have any intention of selling. I am told that total production was about 285, by which time Ithaca Gun Co. figured they were too expensive to make to compete with T/C and every other tom, dick, and harry selling "Hawkins" at the time. Saw a real clean one at the Syracuse NY gun show last year for $850. If you can get one for $300 jump on it, you won't regret it. Mine attracts admirers at shoots all the time.
Bought it with a broken mainspring for $130 last year from a guy who didn't know what it was, had Dixie Gun Works replace the spring for ~ $10 and it shoots great. Took off and saved the narrow nickel silver blade front sight, and installed an old Lyman #17 with a nice patina that matches the rifle. In the woods the silver blade might show up better, but for punching paper, I'm glad I have the Lyman - couldn't see that silver blade too well in bright sunlight, but it will be easy to replace when the time comes, and I can choose whatever insert I want to use in the Lyman. It works just fine with the original buckhorn rear sight. With the thick post insert she shoots to point-of-aim at 25 and 50 yds. with 80 gr. 3F, a .495 Speer ball, and .018 ticking spit patch cut at the muzzle.
So go for it and have fun!