Just my personal memory, two examples:
First sound card was a ct2270 back in 1993, that's a "sb 16 value edition". (retail box, cost me 220 german marks...)
They mainly omitted the wave blaster header. It was noisy AF, but all SB were back then.
Second, a "bulk" SB 32 PNP, that was basically an AWE 32 value, also cutting the wave blaster and I think, some onboard memory. Other than that, solid card.
"value" or "budget" offerings in general, they don't necessary deprive you of anything essential - much of that is merely marketing bs to offer a product to a less solvent clientel while protecting higher value for their "premium" products. The technical term is "price discrimination".
There's also that "AWE64" gold, imho the "gold" part really is mere bling-bling.
So, in general, "creative labs" are crooks in many ways.
The signal quality was bunk, they used all the worst components, the cards were all kinds of bugged. You don't become market leader by having high standards...
But OEM products may simply mean that you provide a product in bulk and take minor precautions that those items don't ruin your retail business.