As a Catholic of Jewish heritage who has seen his share of Seders and has a good friend who is a rabbi, I have it on good authority that there is nothing in reference to the first Passover in Egypt along the lines you mention.
Biblical scholarship and some tradition holds that the narrative of the first Passover in Egypt is written from the standpoint of reflection, much time after the original event took place.
This means that the command Moses received and gave to the Israelite people to follow is not as much a recording of what was actually said as it is teaching the Jews in the context of the Exodus tradition on how to observe Passover. In other words, what you are reading is what people did through the literary device of a command.
Likely Moses’ original instruction and how the people put it into practice formed the final tradition that became the written text. If this is the way it happened, then indeed the command to place blood on the doorways and eating the lamb was followed by all the Israelite people or reflected the popular practice.
There is some scholarship (both Jewish and Christian) that suggests that the Passover held by the Jews in Egypt came from a traditional observance of Abraham and was actually converted into the original Seder at the time of the Exodus. The unleavened bread, for example, was a major change that occurred due to the fact that the Exodus made it impossible to wait for the bread to rise. (Note how Exodus 12:39 makes it sound as if the use of unleavened bread came about to reflect history–not necessarily because the instruction to use unleavened bread came first.) The instructions of Exodus chapter 12:1-20 are believed to be a much later interpolation into the original Exodus narrative, the legislation being of a time period not concurrent with the original Seder in Egypt.
This is why there is no mention of people not observing the original Passover correctly. It is likely that the commands reflect what originally happened, though this does not dismiss that there was some instruction from Moses to begin with.