HD 130 with odd feature

Hi all. I found a head with 4 button supports on the base rather than the typical rubber strip bumpers. I never saw one like this before so I wonder if it's a proto or early design. It has the old font knobs and the backside has the space b/w the serial number plate and larger plate. I know it's an early one. Just wondering if anyone's seen this amp head with the 4 rubber feet versus the strips? Looks unmodded save for a new power switch. I may be forced to sell. THX