Is "Unknown" a valid option for coated side?

[StephenCzarnecki]

When I look at the w7.mdb GlazingProperties table there are some records that have "Unknown" for the Coated_Side field. While these records seem to all be old-style frits it does give rise to the question if "Unknown" should also be a possible value for WinCalc to handle. Should "Unknown" be an allowed value for coated side going forward? If so, how should it be handled?

[jcjonsson]

Using Optics I see two entries in IGDB (ID 9730 and 9731; 6XIRClr.OCN and 12XIRClr.OCN) and is a bit baffle that they managed to sneak that in in v73. I will have to update those.
For old frits it is even more complicated, I would not worry about it.