There are two constants in the GB community.
Amazing replica builds and colour debates
The problem with this is we're simply not going to get an accurate representation of the true colour during production either in the movie or in production stills due to the many variables such as film stock, lighting etc just as we've seen from similar debates with both the suits and the belts.
But, discounting modern reference images that's all we really have to go by.
Now if the connectors appeared to be consistently grey as the elbow pads do throughout all of the movie and in BTS stills then I would whole heartedly agree that they were most likely grey during that time.
However, they simply don't.
The fact alone that they appear to be tan in multiple scenes and BTS stills suggests that they were tan back at the time of production as a purely grey coloured item (once again like the elbow pads) simply won't exhibit the oddly wide range of colour shifting that a tan/khaki item would.
A colour shift which we've seen time and again with both the Suits, connectors and belts.
I realise that plenty of folks will always be of the firm belief that the connectors and belts for that matter were grey but I've seen enough evidence to the contrary to have to agree to disagree.