Not a series I'm familiar with. However with Charles I coins, some die sinker's errors do sell for more, particularly if recognised in a publication such as Spink, or an example having been part of a well-known collection. However, general legend variations are perhaps not so sought after. Certainly with that series, my feeling is that the number of collectors who specialise in errors is very small. And the general trend is, with most everything else, errors and rarity take a very much second place to condition these days. However rare it might be, if the coin doesn't have 'eye appeal' I doubt it will command the premium that it might have a decade or two back ... .