Within the Catholic church, it is common to "baptise" bells when they are installed, giving them names (usually the names of saints), and assigning them godparents. For example, the large bell in Notre-Dame cathedral, Emmanuel, was installed in 1681, and as noted in wikipedia:
The bell's baptism was held on 29 April 1682, officiated by archbishop
François de Harlay de Champvallon. The chapter invited the king and
queen, Louis XIV and Maria Theresa, to serve as the bell's godparents.
The practice goes back centuries - in 789 Charlemagne even issued an edict forbidding it, although this does not seem to have been greatly followed. The similarity between baptising the bells and the true sacrament of baptism was remarked on by Le Sueur:
"the imposition of the name, the godfathers and godmothers, the
aspersion with holy-water, the unction, and the solemn consecration
in the names of the Father, Son, and Holy Ghost, exceed in ceremonial
splendour what is common at baptism, in order to make the blessing of
bells more highly regarded by the people. Real baptism" he remarks,
"may be administered by all kinds of persons, and the rite is simple;
but in what is done to the bells there is much pomp. The service is
long, the ceremonies are numerous, the sponsors are persons of
quality, and the most considerable priest in the place, or even a
bishop or archbishop officiates."
Before the Reformation the practice was common in England too. An interesting example comes from the parish accounts of St. Lawrence, Reading, in 1499:
"Itm. payed for haloweng of the grete bell namyd Harry. And
mem. that Sir Willm. Symys, Richard Clech and maistres Smyth beyng
godfaders and godmoder at the consecracyon of the same bell, and
beryng all o'. costs to the sufrygan."
So the practice of baptising bells would have been well-known to Dickens. I have not found any account of "silver mugs" though. This may either be an extension of the metaphor by Dickens (as it is common to give silver tankards or goblets at people's baptisms), or may be a more obscure/local part of the tradition.