In the old rite (pre-Vatican 2) the priest puts a few drops of oil in the font prior to baptism. Not sure if that is still done in the new rite.
Here's my question: what does 'invalid' even mean within a Reformed context? In a Roman Catholic context it means that the sacrament 'didn't work'. In the case of baptism it would mean that the infusion of sanctifying grace was prevented either because of defect in matter or intention. Since we Reformed don't believe in baptismal regeneration, what does an 'invalid' baptism mean? I was baptized as an infant in the RC and wasn't required to undergo the sacrament again when joining a Presbyterian church.
I'm not presuming to comment on any particular administration of the sacrament (or lack thereof), but think of the Lord's Supper being administered in a private household by a bunch of college students with no ordained minister, no preaching, no fencing, etc. Is that a valid administration of the Supper? I'd say no.
This is different than the Lutheran church administering the Lord's Supper, where we would disagree with all that is going on - certainly with all they think is going on - but it is still valid.