=IF(AND(ISNUMBER(VALUE(LEFT(A1,1))),MID(A1,2,1)=".",ISNUMBER(VALUE(MID(A1,3,1))),ISTEXT(MID(A1,4,1)),ISNUMBER(VALUE(RIGHT(A1,2))),LEN(A1)=6),1,0)

=IF(
  AND(                                 --- ALL conditions below must be TRUE
    ISNUMBER(VALUE(LEFT(A1,1)))        --- char #1 must be a number
   ,MID(A1,2,1)="."                    --- char #2 must be .
   ,ISNUMBER(VALUE(MID(A1,3,1)))       --- char #3 must be a number
   ,ISTEXT(MID(A1,4,1))                --- char #4 must be text
   ,ISNUMBER(VALUE(RIGHT(A1,2)))       --- char #5&6 must be numbers
   ,LEN(A1)=6                          --- the string must be 6 characters long
  )
 ,1,0)                                 --- if true output 1, else 0