Amateur Engineering
Making a cover assembly with heavy clamp load is simple. Making one that delivers acceptable lift, temperature dissipation, durability and burst strength, matched with friction material and damped, properly tested and warranted is not that simple. Amateur Engineering presents well and delivers poorly.

In the example above, the builder balanced the cover by drilling through both the housing and the casting therefore weakening the casting and compromising the cover. Very poor engineering which weakens the casting.

Used parts
A used standard cover assembly can be stripped, reconditioned and sold as an upgraded clutch. Signs that you need to approach a product source with caution include:

Shot blasted covers
A used cover pressing can be shot blasted and coated to present as new. It will present as an even mat finish with a clear coat of varnish. You should be able to see draw marks on the pressed metal cover and a shine to the metal or plated finish.

Paint
Paint can be used for aesthetics. In other cases it can be used to hide prior use, flaws, defects, wear, witness marks etc.

Grinding to remove brands, part numbers.
You need to know the origin, and therefore the quality of the part. In the example above the source codes
were ground off to disguise the origin of the product.

Close enough is not good enough
The clutch plate above has had the friction material removed to show how the seller has basically used a punch and hammer manually to flatten segments. By flattening the segments they were able to compensate for poor lift in the cover assembly. Amateur engineering.