Semi-autos
A Browning Hi-power
A decent 1911

Wheel Guns
Colt Python, 4 or 6 inch. Blue or stainless.
S&W Mod 66
S&W Mod 19

A snub revolver. Probably something like a SW 36, K38, or Dick Spcl.

I wasn't in to semi auto until 1970. Then they were only High Standard target pistol and Colt Gold Cup.
The first non target SA I got was a PP in 32ACP. But it did not last long with the extreme slide bite it gave me.
And in 1968 I was a a freshman in college, and a semi hippie

Smith & Wesson introduced the first Model 66 in 1970. You could have carried a Model 60 in 1968.

I currently carry a 65 vintage Smith Mod 40 centennial,

Maybe a S&W 39 when I wanted a big gun and a S&W 60 for a pocket gun.

Colt Python

1964 - At Cleveland, OH, USSS Field Office with the
approval of the SAIC, I carried my personaly owned
Colt 357(the forerunner of the Python). Great firearm! Still have it and will NEVER sell it.

I was too young to carry in 68 having graduated high school in 72. However, my father was on the job then and carried a Hi-Power in addition to his S/W department issue Revolver. I have the Hi-Power now and carry it from time to time.

Since I was drafted in '63 and Uncle Sam gave me a M1911A1 to carry around SE Asia...by '68 I was carrying a Colt Commander in .38 Super

In 1968 the only pistol I had ever shot was my Dad’s Colt Woodsman. He carried it only when deer hunting. I swear it was full auto. Is that possible? Pretty sure when I was much younger than in ‘68 he entertained himself watching me shoot it, and I emptied the magazine with one trigger pull, and ended up on my butt.

I can tell you what I was packing in my Bell product: A S&W M10 pencil barrel RB, with MPDC on the back strap. Later learned that the Army got a load of them intended for the D.C. Metro Police. I later packed a BHP and an Ithaca 12 gauge cut down to about 13". Later got a 1928 Thompson from a Zoomie (USAF) guy I brought home, but with a half dozen drums was to heavy for the AC, detracted too much from useful load, back to the Ithaca.
Only deployed the subgun once, but with a type C drum it was awsome.

Those who are advocating a Browning High Power:

Are you taking current thinking about the utiltiy of high cap 9mm pistons and applying it to back then? Because I wasn't aware of the BHP being all that popular in the late 60's early 70's. IIRC 9mm was considered anemic, and revolvers still ruled. If there was a king of duty guns, it was something in .357 magnum. How many people where actually carrying BHPs back then?

Smith Model 19
Colt Detective Special
Smith Model 39
BHP
Smith Model 38

S&W Model 39. At the time I was impressed with what Thell Reid could do with it, and Illinois State Police had adopted it as their issue sidearm. 2nd choice would be S&W Model 15 4-inch, I could really shoot that gun.