1990 Chevrolet 2500 Pickup Q&A

1990 Chevrolet 2500 Pickup Question: ODOMETER ROLL OVERS

I HAVE A 1968 CHEVY CHEYENNE WHICH THE ODOMETER READS 68,000 DO THESE OLD TRUCKS ODOMETERS ROLL OVER? I NEED THE READING FOR INS. THANK-U FOR ANSWERING -
Answer 1
Yes they roll over but usually the left number would be slightly higher than the other numbers if it rolled over, So if they line up evenly it probably didn't roll over -