hey all, 

1) I need to replace my freshwater thermostat housing on my 2003 Universal 35 BC.  In order to do this I need to remove the F/W pump, and will need to order a new gasket.   On the Westerbeke parts diagram, for that gasket, it gives the options for either a paper gasket "to date code E412"  or a stamped steel gasket "post date code E501".    Some of the other required parts for the thermostat housing  have a before/after distinction of year 1998, but I have no clue what this code stuff refers to.   

2) one of the bolts for the f/w pump also has a confusing distinction: the M6 bolt for "DIN 931" or the M8 for "DIN 127"....

Does anyone have experience with these parts and know how to dintinguish what I'll need based on these codes/numbers?

I wish google translate spoke Westerbeke.... 

Thanks in advance, 

Brad