Are Promo-DJ Copy stamped vinyl better?

I've always wondered if a record stamped "For Promo Only" or "DJ Copies - Not for Sale" were more likely first edition/early stamps. Most of the ones I've have sounded just fine but I was wondering what those of you who worked in the music, radio, and related industry might tell us about the pressings with these stamps.
Promos tended to be---but weren't always---early in the run of pressings. So better quality is a possibility.
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Yes much better. Most of my collection are all promo pressed. Of course you do run into the risk of unplayable records or even unbalanced ones due to high frequency of usage. But still I think the risk is worth taking for promo copies.