Are road bike shifter hoods compatible across models? I've been using Shimano Sora Shifters since about 2012 .. probably one generation before the current
(https://bike.shimano.com/en-EU/product/component/sora-3500/ST-3500.html)

The rubber covers are now corroded and slimy so I want to change them, but I am not sure if they are available for an old model. I’m wondering if I use a cover for a different model, how likely will it be compatible?

Anyone familiar with this?

Thanks in advance :)
In general, shifter hoods are not compatible between models. Campagnolo has had three different designs since the 90s and Shimano has had many more. If you know the exact model and year of your levers, you should be able to find both original and third party replacement parts online. Competent online stores should have a selection of hoods and list for compatible levers for each.