After a discussion on the topic I found out that Oxford Dictionary Online [courtesy of Grammarphobia; Oct 2016] has a usage note stating that
Historically, dice is the plural of die, but in modern standard English dice is both the singular and the plural: 'throw the dice' could mean a reference to either one or more than one dice.
and Longman [adjusted slightly], for instance, concurs
dice [noun] [count] (plural [also] dice) [(in singular, also die): a small block of wood, plastic etc that has six sides with a different number of spots on each side, used in games
Which unsurprisingly surprised me. Now, I have long ago accepted that languages are living things and I am fine accepting change, however in this particular case I am not sure just how accepted this use is. The Oxford dictionary referred to makes no mention of this use being slang which suggests it should be valid in 'proper' English as well and no reference is even made to die except as a 'see also' and the historical use.
So, does this mean uses like
We lost one dice whilst playing the game yesterday.
The 3D artist was developing a dice model, to be printed later.
are both valid?