In the past, the Pistol Safety Inspection card was not a bearer instrument and the law only required that the handgun be presented for inspection within 10 days of purchase. There was no requirement to keep or carry the certificate, but it was smart to keep it to prove you complied with the law in case the records were lost.
Safety inspections are a thing of the past, but the Issuing Agency Copy and the MSP copy of either the Pistol Sales Record (with a CPL) or the Pistol Purchase Permit must be mailed or delivered to the issuing agency (local PD or County Sheriff) within 10 days of purchase (the gun is no longer presented and no certificate is issued) and you now must have the Buyer Copy of the record or permit in your possession for 30 days after purchase when the gun is in your possession. The 30 day provision is intended to give the authorities time to enter the data in LEIN.