Could I use the old sock and just clean it good?
it depends on what condition you find it in... if it has been there for a long time the spring that manages the small bypass could be broken or rusty, filter difficult to clean, full of crap.
given time job takes to remove the tank, and the little expense to buy a new one, it would be much better to change the internal fuel socket, I wouldn't even think about it...get the one for diesel with bypass
instead, I would consider eliminating it and putting an external filter, much easier for maintenance, an inline fuel filter of 100 microns is enought,
there are billet ones with an internal stainless steel filter, they cost a bit, but then you have it for life, and it's very easy to maintain