No you need at least Lightroom v5.5 to support the Sony DSC-RX100 M3 or you can use the DNG Converter, which can be downloaded from Adobe - Adobe Camera Raw and DNG Converter : For Macintosh : Adobe DNG Converter 8.5 , to create DNG's from the files which can be read from the existing ARW files.
Note though that there is a correction for the DSC-RX100 M3 RAW conversions in the current RC of ACR (8.6) which corrects problems with conversions at ISO125 and also adds additional camera profiles.
Thanks...that is what I thought was the case. I did use the converter and it seems to work fine, but it's an extra step. I guess I'll have to pony up for 5.5.