I am not sure if it is required in the EF Mass, but most priests would take their watch off so that it would not be visible during the elevations. As well, except for a bishop, a priest would not wear any rings, except those who have a wedding ban as a part of their religious profession (and married priests allowed by the Church).
Also, there isn't any prescription of this, but most priests when they wear a cassock under their alb also have a white shirt with french cuffs (optional I guess).
Today, many priests (and I did up until a few years ago) wear a short sleeve clerical shirt under their alb and no cassock. Thus at the elevations, the priest's forearms are completely exposed, not a very formal look given the formal nature of the Holy Sacrifice of the Mass.
What do you think?