First post - so be gentle if this is complete nonsense... but...
This would appear to be the GH4 that includes the Guitar (the description isn't as specific as I'd like), and their product image is also different to that posted elsewhere.
No online stock - but I did find stock at some stores - so may be worth a punt to reserve it, and if you get there an no guitar, don't bother!
I can find the game alone for £29.99 - but Guitar included bundles seem to be in the £69.99 bracket.
(Bracing myself for being told how wrong I am now....)