[So far not an Answer, just a pointer from some Google supported memory - nice question research BTW]
There are other scenes showing the terminals, for example later on, when he get's his first pay check (and the idea to round up pennies) like seen in this Youtube clip. Here they are setup in a data center (*1). Notable point here are the disk drives in the back (another overview seen here). They are most certainly OEMed CDC 844-2 storage units of ~1972, safe to be scrapped into movie use by 1980.
Bad part, CDC was the essential OEM manufacturer for mainframe peripherals at the time. So unless someone recognizes the exact colouring, labeling and button caps (they differ in colour from the original CDC setup), chances are slim to get an identification.
Additional find: An answer pointing to ICL's 1900 made me looking again, and while I couldn't find any 1900 reference, I came across a site mentioning an ICL 2900 sowing a picture with ICLed CDC 844-2 drives. Comparing the big ICL plaque on the left side with a similar sized but blurry ones in the clip supports the theory a lot. Except, they are blue, not orange as suggested.
So yes, I'd say ICL for the drives might be a great lead ... but leaving the OEM issue.
Since the terminals as well are of lower function and at least as old (early 70s), it might be safe to assume they did come with the drives. In fact, all of the equipment looks rather fitting, so the prop team may have scored a full data center.
So the question might be narrowed down which mainframe manufacturer of the early 70s did use the shown design.
For the terminal itself, the key colouring is quite revealing as it follows standards set by keypunches (like IBM 028, Univac 1710 or alike) (*2). So it must have been designated for a mainframe environment (see the disk drive) as well it must be early on, as this kind of structuring already started to vanish in the early 1970s.
It also reassembles a bit a CDC 711/713 terminal in the way the additional switches below the screen are positioned. Then again, the case shape does not match.
*1 - In fact one has to admire how hard the prop guys tried to make it right and how much the filming screwed that. Just think the incredible noise of 20+ drives, chain printers and alike. As expected many will wear earmuffs. Except, to make the scene work out, no (real) noise was present :(
*2 - In fact, looking at the keys on the left and all the markings on the top row, were today numbers would be present,, it really reassembles a keypunch, not a later terminal. So what we see might be some quite early on non-IBM attempt to a data entry terminal.