[Mr Jody]

For something “off the shelf”, take a stroll down the plumbing and electrical aisles at your local hardware store or home center (or do some online shopping there beforehand). With the various sizes of PVC, copper, and iron pipe and conduit, and associated fittings and grommets, there may be something there that can be used to configure a plug for the holes. You could purchase several possible options to see which you like best, and then just return what you don’t use. You could probably even find replacement pipes for the pulled roll bar that can be capped at a height to match the body. Spray paint to the desired color or finish. Sometimes it is kind of surprising what can be found in home stores that can be used for fabrication of vehicles, and usually for much less money.