I used those moog spring part numbers on my '01 limited, and very satisfied. Jeg's told me those part numbers were for the v8 and the 80871 and 80974 were for the v6. Though on my limited in the front at full droop still needed an inch or so to get the springs in, so used a rented compressor. The rear also the emergency brake cables seemed a bit stretched. Using the springs you mentioned with new moog isolators gave me +2 inches from factory sagging parts.
As for weld on, iron rock off road has them... Another member here had them so i emailed them. Here is the response
We do have these replacement perches available, right now they are not available on our website but will be made available soon. For now you would have to call us to place an order for them, they are $25.
Iron Rock Off Road