No, in fact it is the specifically stated posture for only the priest. Deacons on the altar are directed not to do it. There is no specific direction for lay people, but if the deacon is not supposed to be in that position...
I went to mass where I usually go these days, St. Rose in Sacramento (well, I'd usually go on Sunday). It is by no means a liberal parish, very reverent. I noticed some standing with their hands folded. Most, however, hold their hands up, -- which up till now I though was the proper posture, -- and some join hands in a Protestant way.
There was another moment when most held their hands up, and that was at the beginning of the Eucharistic prayer, -- "Lift up your hearts, -- We lift them up to the Lord". Is this also incorrect?
Thank you both for educating me, by the way.