Hi, Karol,
I think that the LPC1114FBD48/302 and LPC1114FBD48/301 can be used interchangeably.
Regarding the difference between LPC1114FBD48/302 and LPC1114FBD48/301, first of all, they have the same pin assignment, same peripherals, the only difference is the power profiles, in other words, the ROM code is different.
The LPC1114FBD48/302 belongs to LPC1100L series, only the LPC1100L series has the power profiles, it provides two ROM api functions: set_pll() and set_power().
For detailed inf, pls refer to Chapter 5: LPC111x/LPC11Cxx Power profiles in UM10398.pdf.

Hope it can help you
BR
XiangJun Rong