In recent years lots of aftermarket rubber parts have very poor quality. Some small parts like rubber seals may perish in a matter of months in storage, or after installation before a restoration car ever gets our of the garage. Parts molded with natural rubber will total garbage, quickly dry rotting when exposed to the environment and/or swelling when exposed to petrochemicals (grease and oil). Parts molded with Neoprene synthetic rubber are pretty good with grease and oil.

Following repeated complaints, someone finally took the initiative to reproduce MGA front suspension seals as 3D printed parts in Urethane for ultra long life parts (good for decades in service).

3D printed seals in Urethane material -- 12-piece set

These parts are available through Etsy from seller "BoxOfPencils". Last known price was $40-USD delivered. -- https://www.etsy.com/listing/1269588535