Yes you should otherwise the hole in your family history as you so neatly put it will nag you forever!
The records should tell you which regiment he was in, what his trade was perhaps, where he went and when and maybe his medical history while in service. From the bare record you could go further and, for example, if he was in India with xyz regiment, you could research the record of that regiment in the war to give an idea of what he was doing.
Just to anticipate a possible question - you don't need his service number, birth date is OK and death cert is a must. Good luck, go for it.
maxD