Yes, but there are five records of Duncan Macintoshes baptised 1791-1798 with father named John, and there could be others whose baptism records have not survived. It is not possible to tell which one is yours.
You need to collect all the information you can about Duncan and Margaret and their family to see if there are any clues to the older generations.
You could then compare baptisms, deaths and the census to eliminate some possibilities.
The five are
Mother Elspet Campbell, baptised Kirkmichael (Banffshire) 1793
Mother unnamed, baptised in Kiltarlity 1796
Mother Ann Fraser, baptised in Boleskine and Abertarff 1797
Mother Ann Dow, baptised in Perth 1798
Mother Elspet Gordon, baptised in Duthil 1799
There are also six deaths after 1855 of Duncan Macintoshes born 1795 plus or minus 5 years.
They are (with estimated dates of birth, assuming that the age at death is accurate)
Aged 70, mother's maiden surname McLean, 1861, Urquhart (Inverness-shire) so DoB 1788/1789
Aged 71, 1870, Portree so DoB 1798/1799
Aged 83, 1873, Bowmore and Kilarrow so DoB 1789/1790
Aged 82, 1875, Daviot and Dunlichity so DoB 1792/1793
Aged 76, 1876, Stirling so DoB 1799/1800
Aged 89, 1880, Kilmallie so DoB 1790/1791
The 1851 census index at SP lists 7 Duncan Macintoshes aged 50 to 60. I've added birthplaces from online transcriptions and (with estimated dates of birth, assuming that the age in the census is accurate)
Aged 50, Portree (born Snizort) so DoB 1800/1801
Aged 51, Kippen (born Weem) so DoB 1799/1800
Aged 55, Bowmore and Kilarrow (born Killean) so DoB 1795/1796
Aged 56, Kilmonivaig (born Boleskine) so DoB 1794/1795
Aged 57, Daviot and Dunlichity (born Dunlichity) so DoB 1793/1794
Aged 60, South Uist (born South Uist) so DoB 1790/1791
Aged 60, Kinfauns (born Laggan) so DoB 1790/1791
So you can see that there are at least as many Duncan M(a)cintoshes whose baptisms are not in the surviving records. You can probably eliminate most of those whose baptism records have survived, but you cannot rule out the possibility that there was another unrecorded one.