Has my house been insulated?

Hi all,
Just been told recently by a neighbour that the couple I bought my house from had put insulation in the walls.
They weren't sure in what way they said something vague about putting plaster against the dividing walls either side of the house ( my house is mid-terrace ).
Is there any way I could check if this is the case.
I have no way of contacting the former owners as they have emigrated.
Many Thanks in advance.

This is a bit confusing.

Firstly the party walls (walls between terraced houses) do not need to be insulated... the theory being that the room on the otherside is at the same temperature.
Therefore only the front and rear walls need to be insulated.