The HP-67: Very similar to the HP-65, same frame and number of keys, but where the 65 has black programming keys and grey operator keys, on the 67 those are all light camouflage green. Where the 65 has f, f^-1 and g shift keys; yellow, yellow and blue; the 67 has f, g and h; yellow, blue and black. The layout of which function goes on which key is also different, and the top five keys now have upper and lower case programming labels and one function each, rather than one programming label, one mathematical function and that function's reverse.
Actually it must have been an HP-67. They look very similar, but I'm pretty sure his had that big-sigma-plus key, and that military-green color for half of the keys looks very familiar, as well as having the f, g and h shift keys with the blue and yellow modes of the keys both printed below the keys.
Santa Claes πΈπͺππ°π
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