I’ve only ever used one tubular wheelset in my life (they felt awesome on the velodrome by the way), so I’m not expert, But:
From what I’ve read around the traps, most experienced racers who prefer tubulars tend to re glue yearly as good practice. I would recommend you do this from now, since you don’t know the exact history of the wheelset.
It is better to reglue tyres at least once a year, it does dry out.
Tape is ok for certain conditions, but not a good idea for track, or for Aussie climate.
I prefer to use tubs of glue that come with a brush - lot less messy than tubes, and tends to go further.
Pull off the old tyre and see how much build up there is of old glue on the rim- if there is only a slight layer and it’s kinda level smooth the just apply another glue layer over the top, and one on the tyre, refit all straight, then pump up hard over night.
If there is a lot of old glue build up on the rim- use a brass (steel is too coarse) wire brush on an electric drill to gently remove it- go too hard and you’ll mark the rim.
Then wipe the rim down and apply a layer of glue- let it dry for an hour or so, I hang the wheels up.
Apply another layer to the rim and to the tyre ( if it is a new tyre then apply a layer letting it dry so total of two)
Put them together, taking care to get the valve straight- pump up hard (120- 140psi) leave overnight in a cool dry place (else the tyre might explode)
Easy as, but i would not trust old glue- and “stuck on since 2005” NFW sorry.