Got these 2 reasonably complete Tilley lamps. Both are in good working condition. Both have "Tilley" and "manufactured in United Kingdom" stamped on the side of the tanks. The lamp on the right in the pic has a cracked glass and is stamped "972xB" on the bottom. I presume this is the date stamp for month 9 and year 1972? The lamp on the left is stamped "1076", so I presume year 1976 then? When was the 1st x246 produced and then also the last (production period)? Thanks! Are they the x246 models?