Depends how much they are, some dealers want a deposit on extras as a sign of commitment as some Mota customers have been known to order a car with lots of extras and then cancel last minute.
So long as you get it in writing that it is a returnable deposit and no towards the AP it’s up to you if you want to pay for them up front.
I added a £200 option pack to my last order and left the £200 deposit with a receipt showing what it was for and it was refundable.