I don’t know specifically but You could try measuring inside tube diameter assuming it has a machined edge near the portion your looking to seal off from the elements and measure the axle diameter throw in a full floating axle seal, but being there is little chance of debris getting in the...
Also, the ones near the gas line aren’t much to worry about, wet rag, heat it up move on - pics sometimes to identify what your speaking of will help distinguish components clearly for reference
Buy one directly from rock auto, grind it off, no harm in heating it, likely no Oring if there is well just replace it. I’d spray everything with kroil before even attempting
I was going to lean on the switch, go the the auto wrecker and pull one for 5 bucks/ throw the old one back in maybe, beyond that ground, but short to ground back feeding to only your dome light just seems wrong..,