Seams vs cracks in doll

If it's cracks in the resin, it would be recessed, the seams are raised above the resin. The arms and legs are typical points to have seams however! If you can post a picture, I could help more!

 

from your description it does sound like seams, like emmacandyapple said! seams can vary from just slight discoloration where they were sanded down by the company if they're new, to being slightly sanded but you can still feel them, to noticeably sharp in places haha. some companies have more prominent seams than others

 

If your doll is 17 years old it will have mellowed from the original color. Most dolls are cast in one solid color however some company's tan dolls or possibly other special colors may only be that color on the surface. I advise researching for the company if it applies. In the case of sanding a mellowed doll usually the difference won't be so extreme that it's a major eyesore, but in the case of severe yellowing it might be substantially uneven. If it wasn't severely yellowed then the lighter / pinker sanded areas after sanding should catch up in mellowing to the rest of the body within a year or two as it's able to oxidize (speaking from my experience).
Now I think every now and then people have actually gotten a crack along the seam lines. If you could look inside the part you would definitely notice if there was an actual crack running through. It's most likely you just have some heavy seams, which are definitely common and easily sanded off. But for posterity, if you did get a crack they can usually be repaired pretty well with apoxie or a liquid resin if you know how to work with that.

 

Dollstown has a line called the 17yr body as the actual name of the body sculpt. OP said theirs was new, so this name is likely all that was referring to.

 

@pitzela Ahh I'm so sorry to be fair, I do know of this dollstown body, I just misread. The way you phrased it I thought you were being cheeky, like saying someone is "60 years young" for example.

With dollstown fresh and it being new you should be good to go on sanding the seams down. It should not have any noticeable difference if you can sand the seams right after it was made.