Vintage 1975 Doublesided Sherlock Holmes Jigsaw Puzzle 15" x 21" 500 piece *READ

Vintage 1975 Double-sided Sherlock Holmes Jigsaw Puzzle 15" x 21" 500 piece This says over 500 pieces. I counted the pieces and came up with 496. I don't know if it is missing 4 or missing 10 or possibly because some of the pieces are so big they counted as 2 pieces? I did not try to put it together. Does anyone want to try? I am NOT a reseller. I am clearing three relatives' places and selling items that don't belong in the dumpster. I've reviewed all items for flaws and done my best to note them. Each piece is individually and carefully packaged the day it is purchased to ensure you receive your item quickly and in great condition. My post office is only open until 11:30 am on Saturday, otherwise all items are mailed within 24 hours of purchase. Items are in a smoke-free, pet-free home. Thank you for purchasing from me!!