Here is a clip of Czech people at a wedding party singing the chorus "Stodola pumpa" in harmony to "Skladal sedlak". However, since the melody of the latter coincides with what we know as "Stodola pumpa", it may be they're two sides of the same coin. It's a possible source of lyrics. Sadly, all the Google references for "Skladal sedlak" point to this clip, or to other video pages where this clip is linked.