Your 527 will in all likelihood print 'one-atop-the-other' assuming you have worked up a load and fed it what is most preferable. From personal experience I had the 1:9 twist varmint variant that shot the standard 69g SMK with exceptional accuracy, and yes, this was with the 'factory barrel' - never had any reason to even consider rebarreling, as it held its accuracy to-a-pinpoint throughout the time I had it.
No reason to alter the load of 24.4g of N140 seated at Sierra's book length of 2.260....
Incidentally, in the kindest possible way, your 'wealthy friend' might be a decent chap and good mate, but is talking cock
Practice, and practice more, to get your 527 into that one-hole-group you strive to achieve and it will surely achieve it - it was by far THE most accurate 'factory' rifle I have ever had the pleasure of shooting, and I've shot quite a few. Indeed it was so reliable, and the only rifle I've had that could consistently reproduce a 0.5" cold-bore shot to pick-up from where I left off on my previous outing - a remarkable little gun
ATB