All I can say is they are CHINA made I had a feeling they may be but for the price I can replace them twice for the cost of one of the bigger brands which may seriously have china bearings in it also. I just put them in today they look good and are heavy made.
My cover was under $20.00 with shipping from ebay just make sure it comes with grommets inserts (if it the 97up) you will need them and the gasket to be from the same year xj and there not cheap but they do work well and can be reused no sealer needed.
Every early 4.0 I had did this even low mile motors I have even bought all new CCV tubes and lines. Nothing ever worked until I bought a newer 4.0 valve cover mines of a 2001 4.0 had to do a little adapting of the breather hoses this stopped 99% of my blowby. Reason is the older 4.0 valve covers have a bad baffle system in them the newer have a full length baffle. There are pics and write ups on here I will see If I still have the book marked.
As far as bolts I have not got back to this yet so I did not even check the hardware store yet. I called the dealer since I kinda wanted factory bolts there over $8.00 each anyone have some rust free decent shape ones they want to sell?
Would like to hear any opinions on brands locals dealers want $135.00 for good USA ones $60.00 for china ones he says no difference he gets them both back at equal rates. I found good brands timkin and national on feebay for around $85.00 each thats the way I am leaning right now.