1st Congrats!
2nd if the Pastel is a male but was sold to you as a female there is definately a price difference. An adult female pastel definately has a not only a higher $ Value but then you have to consider the time it will take to get another true female pastel up to breeding size unless you get one that is already an adult.

Think of it this way. If he was a female you could purchase a baby male other morph and be producing combos in the next 1-2 years (Males mature faster). Since he is a male you would need to purchase a female morph to make combos, if purchased as a baby you are more likely looking at 3-4 years to produce a combo.

I personally would contact the seller about the mix-up and see if they would offer you something to make up for the mix-up.

But then again, if you are happy with the animals you have and the mix-up doesn't bother you since you are possibly getting babies in the near future then CONGRATS!