I'm no guru, but, yes there are repros offered by Richard Clark (site owner). Other members may have NOS replacements in their stashes, as well. To remove them you need a socket the same diameter as the outside metal sleeve of the bushing. Set the mounting bracket on another socket that is larger than the bushing (as much as possible while still supporting the bracket). Drive the bushing out with as little pounding as you can get away with. I have had these come out easily, and others that required some determination. If you plan to try to reuse the bushings, it is very important that the socket used to drive the bushing out of the bracket be as close to the outside sleeve diameter as possible to avoid damage to the sleeve. If you have a press, using it is preferable to the hammer. Also using some hardwood, brass, or aluminum to protect your socket from the hammer is a good idea. Good luck...and go slow...
...bert
Oh yeah...A small amount of penetrating oil around the outside will also help to loosen things up.