How old is barwick clock model 4992?

Hi I also have a Barwick mantel clock model 4992 its made by a clock co Howard Miller. They made these clocks in different years mine was made in 1973. On the back plate of the movement were is says like Howard Miller and stuff like that it should have a number like 73 or 74 on top of all the Words. That is the year it was made. Hope this helps.