That may be what was intended for that distributor. Alot were intended for had low intial timing and quickly add advance just above idle.
If its a 'rebuilt' unit, then can't say what it was supposed to be. If its original, the tag number is the part number and can sometimes be looked up.
Two things to get a handle on what you have.
1. RPM of the initial timing. 5 deg BTC at 550 rpm and 5 deg BTC at 1100 rpm makes a huge diffence on the curve.
2. If you can, measure timing from the slowest rpm you can get it to run to as high as you can measure it. Measure every whatever is convenient. 250 rpm or every 2* increase. Either way will show the curve sufficiently to see what you have.
