I have been studying in UK for the last 3 years for my Bachelors which i have just completed .... well thats about me

My greatgrandfather served with the Royal Army in 1860s in the Indian Subcontinent ... He wasnt exactly in the Army because he was son of the ruler in one of the provinces in India ... so he helped the Army to free soldiers from some warlords in that era .... as recognition for his services he was given a certificate which allowed his descendants to take British Immigration upto 7 generations ... none of my family members took that path and now i wana take up this option as i have been in england for the last 3 years and am pretty much settled over here .... i do have the original document with me which is dated back to 1860s....
my question is would i be able to take up this option or not because its more than 140 years and I have searched alot on the internet but couldnt find anything related to my case .... help wud be really appreciated
cheers
sid