All good!
Yes, that's correct, "B" for Interior.
B = "Minor repairs are not necessary. The most popular grade for export. Very clean interior."
And your car scored a "4".
4 = "The car is under 150,000km The exterior may have some scratches / scrapes and dents.
The car is in above average condition. No Crash history. The interior may have some tears, cigarette burn marks, and / or stains.
They will require some minor repair. The auction sheet will tell us in more detail. Generally a 4 grade car is a good target and the most popular for export. Price range will be in the top 30%."