Check the listing for details. 1988-S PROOF SET OGP IN EXCELLENT CONDITION CAMEO. Made in United States. Listed at 8.99 USD. The 1988-S Proof Set OGP is a highly sought-after coin collection from the United States Mint. This set includes coins that have been struck with a proof finish in San Francisco, making them in excellent condition for collectors. The set is certified by the U.S. Mint and contains uncirculated coins from the year 1988, making it a valuable addition to any coin collector's portfolio.