Hello, I have just taken a movement out from case with same numbers,340-020,to clean it.And with,TEMPORA, on back plate,and Alexander Clark,on dial. But in all cases made by HERMIE.If you look just above the 340-020 stamp,you will see the year stamped.Found mine as it was hidden from view by a lever,70,so mine was made in 1970. Hope this helps,cheerio. 28/12/08
MR. J. Devlin., December 2008