Hi!
They are both young piggies but we cannot age a piggy by their weight. Your can cover babies from ca. 6-8 weeks to teenagers or even small adults (runts). The birth weight can vary from 40g-120g - so the biggest are three times larger than the smallest; this will carry through the whole life with the possible weight range getting much larger in adulthood. Any weight charts only work for a minority of piggies and not the majority of them and are frankly not worth the paper they are printed on.
How long have you had your piggies and where did you get them from? That would help to narrow things down a bit more.
Please take the time to read our weight guide. It will explain things a lot better and in more detail; including how you can work out whether your piggies are a good weight for their current size ('heft' or BMI) - and that is the measure that REALLY counts. As long as yours are a good weight/size ratio and on a good general diet, they will reach their genetically determined individual optimum weight and size for a healthy and hopefully long life. As long as yours are healthy, active and happy, I would not worry and enjoy them as they are for as long as you are given.
Weight - Monitoring and Management
Long Term Balanced General And Special Needs Guinea Pig Diets