The one penny in exists with "Specimen"
overprint, Marcus Smith type D5. It seems likely that they were
produced by De La Rue & Company for their files.
Proofs
The one penny in lilac-rose shade exists imperforate on
watermarked paper. These are presumably plate proofs on stamp paper. These are
frequently found with fake cancels offered as genuine imperforate varities.
Specimen Overprint
The one penny in lilac-rose shade exists with
"Specimen" overprint, Marcus Smith type D5.
Imperforate plate proofs also exist with the same overprint but no image is
available. It seems likely that this was produced by De La Rue & Company for
their files.