It depends on the dealer. Some dealers do get blems at a discount and pass the savings on to their customers. However, it could be a scam. The dealer that I dealt with for many years always had a "blem" to sell. It was either a blem spa, or a swimming pool box that got damaged, or something fake to get the customer to buy at a "discount" but was really their reg price, just re-worded.
Now, having said that. If the spa is what you want, and it is the price you want to pay then buy it. A small surface blem is not going to change the performance of the tub.
Side note: I think consumers are way too caught up in the search for a "deal". The amount that gets rung thru the cash register is the price you pay not the amount you "saved".
So the "original" price really doesnt matter.