It depends a lot on the frequencies involved and the length of the traces. It also depends on how precise your impedance matching has to be for your application, so we would have to know more about the details. I have had to make adjustments to the value or size of resistors and capacitors at 1.8 GHz and up, but below 500 MHz the effects are very small and can be ignored with virtually any size of surface mount parts. For example, at 5.5GHz when we use discrete parts in an RF transmission line, we are careful to choose a size of component similar to the width of the trace. Often 0201 surface mount parts are used on boards with more than 6 layers where impedance control is important as the traces can be quite narrow.
Consider the pad size used for your existing components. If they are really wide compared to the 50 ohm trace, then they may have to be changed if the length of the pad is more than roughly one twentieth of a wavelength at, oh, lets' say the fifth harmonic if digital. For an electrically short pad length, the added reactance is like a point of shunt capacitance, and the amount is very small (like perhaps 1 pF) which can often be ignored at lower frequencies. But if your pad is long relative to the wavelength of the signals on it, then you have to consider it another piece of transmission line, which gets complicated. For this reason, you may have to choose surface mount components that are a similar width to the traces, but this problem can be ignored below, oh, I would say below 1 GHz.
On the other hand, if my fundamental frequencies are below 100 MHz, I would probably not care at all what affect the trace impedance control will have on my component values. I'm not sure if others would agree with me on that, but again, it depends on how precise your application is.