The stamping on the side of the X246A founts, "TILLEY Manufactured in United Kingdom - Model X246A" started on the 1961 straight legged X246A or 'Guardsman' if you prefer. On the more usual X246A lanterns the stamping is like this right through to February 1964. A common (pre-mid 1964) X246A lantern. The 'I' in the word IN starts under the left side of the 'Y'. This following text is the part that is missing from later X246A production models. The evidence shows that models stamped in May 1964 through to December 1964 and an unusually late dated one from Oct 1965, (thank-you @Anthony for confirmation), and probably a 1966 one, do not have this 'Model X246A' stamping at all. They just have the same text that appears later on the X246B models, namely: "TILLEY Manufactured in United Kingdom" I have not yet been able to find a March or April 1964 to determine what they have but February 1964 has the full earlier stamping with the Model X246A notation. Interestingly the late X246A text and the X246B text, whilst the same, are not actually identical in position. The 'i' in the word IN starts in a different position under the 'Y' in TILLEY. An X246B lantern. Note the 'I' in the word IN starts under the right side of the 'Y'. So if collecting Tilleys it might pay to pick up one of the latter made X246A lanterns. Thanks.
@Andrew T Looks like June 1964 and this fits in nicely with those later ones without the 'Model X246A' stamp.
I did have a March 64 lamp some years back before selling it and it was stamped X246A. I think it was April of that year, or very late March when they ceased doing it.
@podbros Without doubt imo. I recently sold a 10/64 BR49A and it had no stamping, so very likely all model stamping cessated circa 4/64.
