Yup the actual mirror unit Jassag Mk2 and as Jens says the arm, sucker and bracket ( the important bits!) are what make it the one offered aftermarket for the Mini. Fitted to Radfords, the odd works rally car and even racer, that's a particularly mint example Tupers!
Just realised I've got a black one fitted in my Series 2 XJ6 but the stem is a different shape to compensate for the low roof profile. Looking at my Mk2 S and Jag stood next to each other in the garage the Jag is bearly two inches taller than the S!
Last time I looked at buying a chrome 608 for the Jag it was about £120
Edit : Tupers - just looking at the mounting bracket on yours again and it looks like it could also be used in some classic open top two seaters, mounted upsidedown on the dash rail instead of the top of the windscreen
Its an accessory Lucas608 mirror with the universal bracket - the ones fitted to Jags have either a triangular bracket or a bracket that forms part of the stem. Those fitted to Rover P5 + P6 have a thread coming out of the back of the mirror which bolts to a cast bracket.
Your mirror is the most desirable variant as it fits straight into a mk1 or mk2 mini (fitting a Jag one requires cutting the bracket and drilling holes) . There are two variants on the shape of the nut on the stem linked to the number of rivets in the back plate of the mirror - some have the tapered nut like yours whereas some of the earlier 5 rivet mirrors (fitted to Jensen C V8 for example) have just an ordinary chromed nut.
The rubber sucker is from a 1965 standard Mini interior mirror - this was superseded by the clear plastic mounting cup on the 1966 mirrors (and obviously not present on the earlier black crackle mirror). Fitting one of these to a 608 stops the mirror from vibrating and makes it far more useable - the works modified the 608 mirrors used in 1966-67 and 68 season cars using the Barnacle off a Barnacle mirror...