I must apologise.
As far as i can remember, my info on Hobbs’ desire to have the company’s products only marked HOBBS came from the company history, and I do not have a copy. Nor do i have a Hart famioly tree, but there were surely severaL members involved over the years.
Hart had to wait until Hobbs’ death, in 1892, before he could add himself to the company’s legal name. I formerly had a box of Hobbs cabinet locks collected from Barclays Bank branches, ranging from end of 19C to probably just post-WW2. There were detail differences in the stampings, such as typeface and size varying, but all were only HOBBS, as indeed Scott Klemm’s catalogue page shows.
However, I have looked again at a cell lock I have, the trigger-action 4lever with indicator and spherical fixed handle. Apart from my own one i have not looked closely at this lock which from end of 19C onwards was fairly common in police stations and prisons, including army prisons. It is clearly marked HOBBS HART CO., and mine came from a police station of c1890’s.
Perhaps in the elation of finally having his name recognised (Hart had been running the company since Hobbs had returned to USA and other challenges) he triumphantly put his name on a few locks? Also, there are safeplates marked Hobbs Hart.
Such locks are probably not a good dating guide.