The longhorn did not come out till the late 60's with the new body style. Not sure if it was a first year 67 or next year 68 option. I have seen lots of 69s with it. So that would not be something you are looking for.

I have a 1962 K 20 fleetside long bed up. So yes what you are looking for does excest. It may be a bit hard to find.

Depending on how you plan to use it I would go with a 63. It still has the cool curved windshild plus you get the better engine 292. Yes the 235 and 261 were great but for real daily driving I would go with the latter.

63 would not have the pod turn signals. And single headlights.

But yes what you are looking for was a factory truck. Best kind to get is an old fire brush truck.

Good luck

1947 1Ton stepside
1962 K20 Fleetside
1962 C40 12' flatbed
1963 C10 Stepside
1963 C20 Fleetside
1965 C10 Stepside (Daily Driver)
1973 C20 Stepside fire truck
1973 C50 Utility truck Houston Power & Light