Good looking jeep.
There are plenty of places to find most pre-76 jeep parts. Our intermediates (72-75) do have some parts that are hard to find, but search places like Quadratec and 4wd Hardware and others for most stuff. The Internet is your search friend. I also advise joining EarlyCJ5.net forum. Great info and great people with knowledge of our oddballs over there.
Your rollbar looks like mine in my 73. Mine is out of a 76. The 76-79 rollbars sit on top of the fender wells and have a rear slant on the main hoop similar to the windshield angle. The correct rollbar for the 73 is one that has a vertical main hoop.
1973 CJ5, 304, T15, D20
2009 JKU, Rubicon
2005 TJ, X, 4.0, 6 speed