So on start up lately, my oil pressure has read higher than normal. I drive around for 5 minutes and then it goes down to normal range. Why is this?

Heres what I have:

1964 F100 stock 292 Y, never rebuilt

Year old oil pump with maybe 1000 miles on it

10W30 oil and change oil about every 2000 miles

SW oil pressure gauge

On a cold motor and after warm up, once the choke has been depressed, the pressure stays at 55-60 (thats where it is with the choke engaged) My normal range is 35-45. Then it wont drop until I drive around for a while. Should I be worried?

1964 F100 292YBlock