This has nothing to do with "digit shapes".
The "locale" cannot change digit shapes. Those are just different Unicode code points, so called "Eastern Arabic numerals",
http://en.wikipedia.org/wiki/Eastern_Arabic_numerals[
^].
In contrast, all the Western world uses "Arabic numerals" in its Western form, in different glyphs and code points which have been standardized in ASCII and other early standards:
http://en.wikipedia.org/wiki/Arabic_numerals[
^].
See also:
http://en.wikipedia.org/wiki/Glyphs_used_with_the_Hindu-Arabic_numeral_system[
^].
Both Unicode subsets are supported by most modern OS by default. You can ignore the locate and use the code points you want in your applications. In any case, it absolutely irrelevant to the fonts you use.
—SA