I try to figure more accurately this issue. Finnish I1-haplotype of I1 was previously timed by Ken Nordtvedtto be about 2100 years old (He pulled his age calculations away from his site last winter). Because Finnish type exists almost exclusively in Finland and whole I1-type is so young the Bothnia had not much time to move to Finland. Swedish Norse and Finnish Bothnia are close branches, but no-one has found their common ancestor (Nordvedt has tried it hardly). So we are in situation that it is not sure that Bothnia came from Sweden, though it is possible. All Bothnia in Sweden seems to be very late types in Finland and probably from Finland.
When we look at other directions for I1's route to Finland, the best guess is Baltic region, because from there population came to Finland, of course not all. This is a very clear-cut idea, but I havn't found reliable data to prove it. T.Lappalainen et al. shows data that gives wonderful hints, but it is not enough to make this credible. This study lists Estonian, Latvian, Lithuanian, Karelian, East Finnish (Savo), West Finnish and Swedish I1 STRs, but only using 10 alleles. I can reach a very reliable outcome with it by using common sense, though it's not enough to all
In the table we can see rows where those ten alleles show typical Bothnia sequenses and results which exist only in Estonian and Finnish columns, not in the Swedish column. This would mean that that particular row, which doesn't include Swedish values is not Norse type. Here is the table
http://www.elisanet.fi/mauri_my/I1/Lappalainen_mtDNAyDNABalticSeaRegion_I1.xlsPlease if you wish download it, I'll remove it tomorrow. Can delivery it later is wanted.
edit Of course T. Lappalainen et al. can have made wrong conclusions with too few alleles.