The new P series uses HD, not HDR. HDR is only in the x900 series (4900, 7900 and 9900). The 3880 and x890 series use the K3 sets.
You can't use the Orange and Green in older models which makes it the HDR set in an older model (7880, 9800 etc). The inks from the x890 series will not be usable in the x800/x880 series.
The rest of the HDR colors are the same as the K3, but the cartridge/chip will be different from the 3880 to the x890 series.
Hope this helps.