The suggesting of a particular UY is normal and they have always had one that seemed to be the particular one being offered.
But, if a new buyer asks for and requests the huge get approval for a different one, I have never heard of someone not getting what they want.
With the exception of that use year being sold out. If you are buying a resort that is not in active sales or is close to selling out, you may not be able to choose your use year, regardless of what hoops the guide and Accounting are willing to go through. Also, not all months have use years attached to them - which might lead to a buyer hearing no and not understanding the explanation (or not getting one other than "that isn't available.").