No, I think it stands for Giancarlo as
@shanez said and is a pre-cursor as
@TheIronMonkey said.
Maybe say ... 'Historically important and rare Savinelli pipe, from 20th century, fashioned by Giancarlo Savinelli, proving generations of development, in sandblast finish with handmade briar accent ring possibly leading to the development of the desirable and highly sought after Mr. G series; pre-tested, near mint or better, collectable, pre-loved, museum quality, mediterranean briar, hand made, significant addition to collection sought after by serious connesseurs; from priavte collection' .... or something like that..... just a suggestion ...