I think that could be the case: Christine is referring to the fact that when pressed glass production ceased in 1953, there was reportedly six months stock remaining to fulfill any orders that might crop up.
I have speculated that perhaps quantities of this stock was sold off to other manufacturers who then proceeded to customise it in various ways. This could, of course, include all those items with strange lids and peculiar customisation, and some Britannia glassware may also fall under this idea as well.