joe
this confused and inconsistent subject has been thrashed over and over (you may know); it is also full of bad theories and reports and opinions the more you look into it.
The Redux thread exposes the best info, but beware some claims are also bad in there. You have to read subsequent articles/ posts to 'improve the picture'.
To summarise, we are left with 2014- TMP link from Sasha:
-- Austerlitz relics, an all light crimson miter, and a straw miter with a dark band, have been identified as belonging to the Narva and Old Ingermanland grenadier battalions*.
*Meaning Musketeer Regiments, First (grenadier) battalions. One of three in each regiment- all wearing it.
In another thread someone was "claiming" that because the only grenadier headgear recovered at Austerlitz were mitres, they all wore them! These TWO units cited above are the ONLY RELICS/ SOUVENIRS known apparently, so citing "ALL" is a bit far fetched and unrealistic. (This from Russian sources).
So, would anyone have differentiated between a grenadier shako and musketeer ones? Given there was the 3 Grenades badge, perhaps. Yet we dont see them exposed or recorded.
Increasing the 'NO' vote (for mitres) by:-
-- An officer's diary indicates the Apsheron grenadier battalion had switched before Austerlitz.
And a 'PERHAPS':-
-- The regimental history of the New Ingermanland [Musketeer Regiment] is said to relate a Nov. 1805 order to change the [facings] miter bags to dark green. However, since the facing change occurred in Nov. 1804, this is an error as to the year.
The latter by inference saying they wore mitres and not shako, because they were 'renewed'. I seriously doubt they would renew the mitre AND THEN replace them virtually unused some months later (the directive 'issued Feb 1805).
regards
dave