Li 150 Special spanish 3rd gear cog

hi, just checked in stickys lambretta manual & the 3rd gear cog size stated for this is 97.2 o/d & 39 teeth, my question is,as I don't have the cog to hand to measure it,the same dimensions as the late pacemaker 3rd gear cog post mod that measures 33.8mm across 5 teeth ? thanks for any info 
