Yup, Pick n Mix, I'm always swaping or "borrowing" parts from my other bikes, I say borrow because I don't want my bike to feel depressed that I took the alloy platform pedals off it and stuck on plastic ones, always leave a bike with the glimmer of hope that the platforms will return
The way I look at it is that what I sell is bikes, but what I buy is parts either separately or in rideable form. Even when I repair other people's bikes I keep all the old parts and enter whatever components are recoverable from them in to my parts bank, and withdraw other parts from my parts bank to use on their bikes.
Whatever 'bikes' I own are merely collections of temporary withdrawals from my parts bank, until I assemble a bike for sale.
My last build off bike, Ten Turing, has aluminium wheels from my neighbour's bike simply because his rear wheel bearings were toast and we could not remove the freewheel. I had a pair of steel wheels in stock that I had not yet stripped down, so we exchanged, and he was up and riding the next day. Two weeks and much effort later and I had that freewheel off.
Unless it is something that has personal meaning to you, chop away.
I cut up my custom swingbike after it tried to kill me one to many times, it was a cool experiment, but flawed all the same... It's parts went into 3 other builds...